A process for recovering iron concentrate and high-sulfur iron concentrate from copper tailings

Abstract

The application discloses a method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings, which comprises the following steps: S1, selecting copper tailings by adopting a method of "magnetic roughing-magnetic cleaning-desulfurization flotation, tailing classification-coarse sand magnetic separation and circulation", S2, separating tailings by adopting a method of "separation flotation-reselection magnetic separation", and S3, "concentration-fine sand magnetic separation-disk magnetic separation"; the copper tailings comprise copper tailings with an iron grade of 30-35% generated in a flotation scavenging operation of a copper ore dressing plant and separation tailings with an iron grade of 32-36% and a sulfur grade of 20-25% generated in a copper-sulfur separation flotation operation; finally, iron concentrate with an iron grade of 62-66% and a sulfur grade of 1-3% and high-sulfur iron concentrate with a comprehensive iron grade of 50-60% and a comprehensive sulfur grade of 10-25% are obtained. The application realizes efficient recovery of iron resources in the copper tailings and resource utilization of high-sulfur products, the iron concentrate has a high grade and a high recovery rate, the process is stable, the environmental benefits are remarkable, and the application is suitable for large-scale comprehensive recovery and treatment of the copper tailings.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing engineering technology, specifically relating to a method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings. It is particularly suitable for the comprehensive recovery and utilization of tailings generated after copper beneficiation in copper mines, realizing the efficient extraction of iron resources and the resource utilization of high-sulfur iron by-products. Background Technology

[0002] Copper tailings are industrial solid waste generated after copper ore undergoes processes such as flotation and magnetic separation to extract copper concentrate. Their emissions are enormous, not only consuming vast amounts of land resources but also potentially causing environmental pollution due to sulfides and other components contained within the tailings. As the world's largest copper producer and consumer, my country accounts for over 35% of the global non-ferrous metal tailings emissions annually, with tailings from mainstream copper deposits such as porphyry and skarn types accounting for over 70%. Due to the complex mineralization process, these tailings, in addition to residual copper minerals, are enriched with large amounts of valuable elements such as iron and sulfur—iron grades generally range from 15% to 30%, with some tailings even reaching the cutoff grade for directly minable iron ore; sulfur is mainly present in the form of sulfides such as pyrite and pyrrhotite, typically ranging from 2% to 8%. Effective recovery of these associated resources could not only alleviate my country's dependence on imported iron and sulfur resources but also reduce the environmental pressure caused by tailings accumulation.

[0003] Currently, the main utilization paths for copper tailings in China include backfilling underground mining voids, preparing building materials, and simple re-selection of valuable elements. However, all of these methods have significant limitations: backfilling mining voids can absorb a large amount of tailings, but it requires a large amount of cement and other cementing materials, resulting in high costs, and it permanently seals away valuable metals such as iron and sulfur associated with the tailings; preparing building materials such as non-fired bricks and roadbed materials has lower costs, but its large-scale application is limited by transportation radius and market demand fluctuations; however, existing technologies for recovering iron resources from copper tailings have many shortcomings.

[0004] First, it is difficult to balance grade and recovery rate. In the traditional roughing-cleansing magnetic separation process, if the goal is to achieve an iron concentrate grade of over 65% as the raw material for ironmaking, the iron recovery rate is usually less than 40%. If the recovery rate is increased by reducing the separation precision, the iron concentrate grade will drop below 60%, which cannot meet the raw material requirements of steel companies.

[0005] Secondly, sulfur removal is incomplete. Sulfur in copper tailings is mostly associated with iron minerals, and conventional magnetic separation processes cannot effectively separate iron sulfide from magnetite, resulting in excessive sulfur content in the iron concentrate (some reaching over 0.8%, far exceeding the ≤0.3% sulfur content requirement for ironmaking raw materials), making it only suitable for use as a low-value blending ore.

[0006] Third, sulfur resources are not being utilized effectively. Existing processes mostly remove sulfur through reverse flotation, and the resulting sulfur-containing tailings are directly stockpiled, which not only wastes sulfur resources but also exacerbates the environmental risks of tailings ponds due to the release of acidic wastewater from the oxidation of sulfides.

[0007] Therefore, developing a technology that can efficiently recover iron concentrate from copper tailings and simultaneously realize the resource utilization of high-sulfur iron concentrate can not only solve the ecological safety problem of tailings storage, but also enhance my country's mineral resource security capabilities, and has significant environmental, economic and social benefits. Summary of the Invention

[0008] The purpose of this invention is to address the problems of low iron resource recovery efficiency, difficulty in meeting the requirements for iron concentrate grade and sulfur content, and ineffective utilization of high-sulfur products in existing technologies. This invention provides a method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings. Through a combination of staged magnetic separation, flotation desulfurization, and tailings recycling, this method achieves efficient purification of iron concentrate and simultaneous recovery of high-sulfur iron concentrate, thereby improving the comprehensive utilization rate of resources.

[0009] To achieve the above-mentioned objectives of the present invention, the method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings is implemented using the following technical solution.

[0010] This invention discloses a method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings, wherein the copper tailings include copper beneficiation tailings generated from flotation and scavenging operations in copper ore beneficiation plants and separation tailings generated from copper-sulfur separation flotation operations. The method is characterized by the following steps:

[0011] S1: Copper tailings processing: "Magnetic roughing-magnetic cleaning-desulfurization flotation, tailings classification-coarse sand magnetic separation and recycling"

[0012] ① Magnetic roughing separation: Copper tailings with an iron grade of 30%~35% are subjected to magnetic roughing separation to obtain magnetic roughing concentrate with an iron grade of 55%~60% and magnetic roughing tailings with an iron grade of 12%~16%.

[0013] ② Magnetic Concentration: Magnetic concentration is carried out on the magnetic roughing concentrate to obtain magnetic concentrate with an iron grade of 60%~65% and a sulfur grade of 5%~8% and magnetic tailings with an iron grade of 14%~18%.

[0014] ③ Desulfurization flotation: The magnetically concentrated concentrate is fed into the iron desulfurization flotation operation to obtain desulfurized froth-high sulfur iron concentrate with an iron grade of 58%~62% and a sulfur grade of 18%~22%, as well as iron concentrate with an iron grade of 62%~66% and a sulfur grade of 1%~3%.

[0015] ④ Tailings Classification - Coarse Sand Magnetic Separation and Recycling: The tailings from magnetic coarse separation and magnetic fine separation are mixed and fed into a hydrocyclone for classification, resulting in classified coarse sand with an iron content of 13%~18% and classified fine sand with an iron content of 14%~17%. The classified coarse sand is then subjected to coarse sand magnetic separation to obtain coarse sand magnetic concentrate with an iron content of 40%~45% and a sulfur content of 5%~10% and coarse sand magnetic tailings with an iron content of 12%~16% and a sulfur content of 0.2%~1%. The coarse sand magnetic concentrate is returned to the magnetic fine separation operation to achieve resource recycling.

[0016] S2, Tailings separation via flotation followed by magnetic separation

[0017] ① Separation and flotation: Separate flotation is carried out on the tailings with iron grade of 32%~36% and sulfur grade of 20%~25% to obtain copper concentrate 2 with copper grade of 4%~8% and re-selected copper tailings with iron grade of 0.2%~1% and sulfur grade of 22%~25%.

[0018] ② Re-selection and magnetic separation: The copper tailings are subjected to re-selection and magnetic separation to obtain re-selection tailings magnetic concentrate with iron grade of 55-60% and sulfur grade of 16-20%, and re-selection tailings magnetic tailings with iron grade of 30-35% and sulfur grade of 22-26%.

[0019] S3, Concentration - Fine Sand Magnetic Separation - Disc Magnetic Separation

[0020] ① Concentration: The graded fine sand obtained in step S1 ④ and the re-selected tailings obtained in step S2 ② are fed into a thickener for concentration to obtain thickener underflow with an iron content of 15%~18%.

[0021] ② Fine sand magnetic separation: Fine sand magnetic separation is performed on the underflow of the thickener to obtain fine sand magnetic concentrate with an iron content of 52%~56% and a sulfur content of 10%~12%, as well as fine sand magnetic tailings with an iron content of 13%~16%.

[0022] ③ Disc magnetic separation: Fine sand tailings are subjected to disc magnetic separation to obtain disc magnetic concentrate with iron content of 27%~30% and sulfur content of 18%~21%, as well as tailings with iron content of 12%~16%.

[0023] The fine sand magnetic concentrate obtained in step S3②, the disc magnetic concentrate obtained in step S3③, the desulfurization foam obtained in step S1③, and the re-selection tailings magnetic concentrate obtained in step S2② are combined and sold directly as high-sulfur iron concentrate.

[0024] Preferably, in step S1, both the magnetic coarsening and magnetic cleaning processes use a CTB-type magnetic separator. Specifically, the magnetic coarsening process uses a CTB1021 magnetic separator with a magnetic field strength of 2000–2500 Gs, while the magnetic cleaning process uses a CTB1024 magnetic separator with a magnetic field strength of 1500–2000 Gs.

[0025] Preferably, in step S1 ③, the pulp concentration for desulfurization flotation is 15%–25%, butyl xanthate is used as the iron mineral collector, and No. 2 oil is used as the frother; the dosage of butyl xanthate is 80–120 g / t, the dosage of No. 2 oil is 15–25 g / t, and the flotation time is 2–5 min. The reagent dosage refers to the dry weight of the copper tailings.

[0026] Preferably, in step ④ of S1, the hydrocyclone classification operation uses a hydrocyclone with a specification of φ400~φ600mm and a classification pressure of 0.15~0.25MPa; the coarse sand magnetic separation uses a CTB1021 magnetic separator with a magnetic field strength of 800~1200Gs.

[0027] Preferably, in step S2①, the separation flotation uses pentyl xanthate as the collector and No. 2 oil as the frother; wherein the collector dosage is 120-180 g / t, the No. 2 oil dosage is 25-35 g / t, and the flotation time is 3-6 min. The reagent dosage refers to the dry amount of tailings to be separated.

[0028] Preferably, in step S2 ②, the re-selection magnetic separation uses a CTN1021 magnetic separator with a magnetic field strength of 2700~3200Gs.

[0029] Preferably, in step S3 ②, the fine sand magnetic separation uses a CTB1021 magnetic separator with a magnetic field strength of 2800~3200Gs.

[0030] Preferably, in step S3 ③, the disc magnetic separator uses a Φ1200mm disc magnetic separator with a magnetic field strength of 2800~3200Gs.

[0031] Furthermore, the process parameters of each step, S1, S2, and S3, are adjusted in a coordinated manner so that the comprehensive iron grade of the product sold directly as high-sulfur iron concentrate is 50%–60% and the comprehensive sulfur grade is 10%–25%.

[0032] The method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings according to the present invention, after adopting the above technical solution, has the following beneficial effects:

[0033] (1) A stable and efficient mineral processing system was constructed by combining the “roughing and cleaning magnetic separation-desulfurization flotation-tailings classification and recycling” process of copper tailings with deep separation equipment. In the example, copper tailings with an iron grade of 31.42% were purified to obtain qualified iron concentrate with an iron grade of 63.54% and a sulfur grade of 1.76%, and the iron recovery rate was greatly improved. At the same time, through secondary treatment of the separated tailings, iron resources were further recovered, and the iron grade of the discharged tailings was reduced to below 15%, so as to maximize the utilization of resources.

[0034] (2) This invention can not only obtain qualified iron concentrate, but also simultaneously recover high-sulfur iron concentrate (including desulfurization foam, fine sand magnetic concentrate, re-selection tailings magnetic concentrate, and disc magnetic concentrate) through the "separation flotation-re-selection magnetic separation-thickening machine bottom flow magnetic separation-disc magnetic separation" process of tailings separation. This solves the problem of waste of sulfur-containing products in traditional processes, which not only improves resource utilization but also generates certain economic value.

[0035] (3) By using the tailings recycling process (coarse sand magnetic separation return to beneficiation operation), the material balance was optimized and the stability of the process operation was improved; at the same time, the hydrocyclone classification and disc magnetic separation deep recovery were adopted to further improve the stability of product indicators.

[0036] (4) Achieving a win-win situation for both environmental and social benefits. Through the efficient recycling and utilization of copper tailings, the resource utilization rate of tailings has been greatly improved, which can reduce the amount of tailings stockpiled by more than 55%, save a lot of land occupied by tailings ponds, and reduce the operation and maintenance costs and environmental risks of tailings ponds; it avoids the problem of acidic wastewater released by oxidation during the storage of sulfide tailings, and reduces pollution to soil and water bodies from the source; the recovered iron and sulfur resources can replace some of the primary mineral resources, alleviate my country's dependence on foreign iron and sulfur resources, and enhance the domestic mineral resource security capacity. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating the principle process of a method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings according to the present invention.

[0038] Figure 2 This is a flow chart of the mineral processing method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings according to the present invention. Detailed Implementation

[0039] To further describe the present invention, a method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings according to the present invention will be described in detail below with reference to the accompanying drawings and embodiments. Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. Reagents or instruments used, unless otherwise specified, are all commercially available conventional reagent products.

[0040] In this embodiment, the raw ore from a copper mine has a copper grade of 0.425%, a sulfur grade of 3.32%, and an iron grade of 31.54%. After beneficiation at the concentrator, the resulting copper concentrate has a copper grade of 22.69%, a sulfur grade of 29.325%, and an iron grade of 35.65%. The resulting copper tailings (from the flotation and scavenging operations at the copper mine concentrator) have a copper grade of 0.036%, an iron grade of 31.42%, and a sulfur grade of 3.32%. The resulting separation tailings (from the copper-sulfur separation flotation operations) have a copper grade of 0.42%, an iron grade of 34.26%, and a sulfur grade of 24.52%. The copper tailings and separation tailings from this copper mine are used as raw materials to recover iron concentrate and high-sulfur iron concentrate. The principle process flow diagram is shown below. Figure 1 For its mineral processing flow chart, please refer to [link / reference]. Figure 2 The specific implementation steps are as follows:

[0041] S1: Copper tailings processing: "Magnetic roughing-magnetic cleaning-desulfurization flotation, tailings classification-coarse sand magnetic separation and recycling"

[0042] ① Magnetic roughing separation: The copper tailings slurry is adjusted to a concentration of 30% and fed into a CTB-1021 magnetic separator. Magnetic roughing separation is carried out under a magnetic field strength of 2300Gs to obtain a magnetic roughing concentrate with an iron grade of 57.65% and a magnetic roughing tailings with an iron grade of 14.92%.

[0043] ② Magnetic Concentration: The magnetic roughing concentrate is slurryed to a concentration of 25% and fed into a CTB-1021 type magnetic separator for magnetic concentration. Magnetic concentration is carried out under a magnetic field strength of 1700Gs to obtain magnetic concentrate with an iron grade of 62.53% and a sulfur grade of 6.30% and magnetic tailings with an iron grade of 14.63%.

[0044] ③ Desulfurization flotation: The magnetic concentrate is slurryed to a concentration of 20%, and butyl xanthate (100g / t) is added as a collector and No. 2 oil (20g / t) is added as a frother. The mixture is floated in a flotation machine for 3 minutes to obtain desulfurized froth-high sulfur iron concentrate with an iron grade of 59.25% and a sulfur grade of 19.98% and qualified iron concentrate with an iron grade of 63.54% and a sulfur grade of 1.76%.

[0045] ④ Tailings Classification - Coarse Sand Magnetic Separation and Recycling: The tailings from the magnetic coarse separation and the magnetic fine separation are mixed and fed into a φ500mm hydrocyclone for classification. Classification is carried out under a pressure of 0.2MPa to obtain classified coarse sand with an iron content of 15.03% and classified fine sand with an iron content of 14.71%. The classified coarse sand is then subjected to coarse sand magnetic separation using a CTB1021 magnetic separator with a magnetic field strength of 800-1200Gs to obtain coarse sand magnetic concentrate with an iron content of 42.30% and a sulfur content of 6.66% and coarse sand magnetic tailings with an iron content of 14.89% and a sulfur content of 0.398%. The coarse sand magnetic concentrate is returned to the magnetic fine separation operation to achieve resource recycling.

[0046] S2, Tailings separation via flotation followed by magnetic separation

[0047] ① Separation and flotation: The tailings with an iron grade of 34.26% and a sulfur grade of 24.52% were adjusted to a concentration of 25%, and pentyl xanthate (150g / t) was added as a collector and No. 2 oil (30g / t) as a frother. Separation and flotation were carried out for 5 minutes to obtain copper concentrate 2 with a copper grade of 4.02% and copper tailings with a copper grade of 0.305% and a sulfur grade of 26.44%.

[0048] ② Re-selection magnetic separation: The copper tailings are fed into a CTN-1021 magnetic separator (magnetic field strength 3000Gs) for re-selection magnetic separation to obtain re-selection tailings magnetic concentrate with iron content of 59.60% and sulfur content of 18.33% and re-selection tailings magnetic tailings with iron content of 32.02% and sulfur content of 24.70%.

[0049] S3, Concentration - Fine Sand Magnetic Separation - Disc Magnetic Separation

[0050] ① Concentration: The graded fine sand obtained in step S1 ④ and the re-selected tailings obtained in step S2 ② are fed into a φ45m thickener for concentration to obtain a thickener underflow with an iron grade of 15.74%.

[0051] ② Fine sand magnetic separation: The underflow from the thickener is fed into a CTB1021 magnetic separator for fine sand magnetic separation. The magnetic field strength of the CTB1021 magnetic separator is 2800-3200Gs, resulting in fine sand magnetic concentrate with an iron content of 54.50% and fine sand magnetic tailings with an iron content of 15.43%.

[0052] ③ Disc magnetic separation: The fine sand is fed into a Φ1200mm disc magnetic separator for disc magnetic separation. The magnetic field strength of the disc magnetic separator is 2800-3200Gs.

[0053] The resulting disk magnetic concentrate had an iron content of 27.41% and a sulfur content of 20.98%, and the tailings had an iron content of 14.79%.

[0054] The fine sand magnetic concentrate obtained in step S3②, the disc magnetic concentrate obtained in step S3③, the desulfurization foam obtained in step S1③, and the re-selection tailings magnetic concentrate obtained in step S2② are combined and sold directly as high-sulfur iron concentrate. The high-sulfur iron concentrate has a comprehensive iron grade of 54.66% and a comprehensive sulfur grade of 19.92%.

[0055] Chemical multi-element analysis was performed on the coarse sand magnetotail obtained in S1④, and the results are shown in Table 1.

[0056] Table 1. Results of multi-element chemical analysis of coarse sand magnetotail (%)

[0057]

[0058] The coarse sand magnetotail obtained in S1④ was subjected to iron phase analysis, and the results are shown in Table 2.

[0059] Table 2. Phase analysis results of coarse sand magnetite tailings (%)

[0060]

[0061] The iron phase analysis results show that the iron in the coarse sand magnetotail mainly exists in the form of iron silicate, with a distribution rate of 93.83%, and a small amount of iron exists in the form of magnetic iron, iron sulfide and iron carbonate.

[0062] After grinding the coarse sand magnetotail samples into smooth and thin sections, the content of various minerals was statistically analyzed under a microscope using the line segment method. The mineral content was then calculated based on the results of scanning electron microscopy (SEM) and EDS analysis. The mineral content statistics are shown in Table 3, in weight percentage (wt%).

[0063] Table 3. Statistical results of coarse sand magnetite content (wt%)

[0064]

[0065] The results showed that the magnetite content in the sample was 0.42%; the main sulfur-bearing minerals were pyrite and pyrrhotite, with contents of 0.71% and 0.11%, respectively; the main copper-bearing mineral was chalcopyrite, with a relatively small content; the phosphorus-bearing mineral apatite content was 0.29%; the main non-metallic minerals were silicate minerals pyroxene and andradite, with contents of 50.46% and 25.58%, respectively, followed by carbonate mineral calcite with a content of 7.49%, and small amounts of silicate minerals such as albite, amphibole, mica, and serpentine; other minerals were present in small amounts.

[0066] Chemical multi-element analysis was performed on the tailings obtained from S3③, and the results are shown in Table 4.

[0067] Table 4. Results of multi-element chemical analysis of tailings discharged from the outlet (%)

[0068]

[0069] Iron phase analysis was performed on the discharged tailings, and the results are shown in Table 5.

[0070] Table 5. Results of iron phase analysis of discharged tailings (%)

[0071]

[0072] The iron phase analysis results show that the iron in the discharged tailings is mainly in the form of iron silicate, with a distribution rate of 92.29%, and a small amount of iron exists in the form of iron sulfide, magnetic iron and iron carbonate.

[0073] After the tailings samples were ground into smooth and thin sections, the content of various minerals was statistically analyzed under a microscope using the line segment method. The mineral content was then calculated based on the results of scanning electron microscopy (SEM) and EDS analysis. The mineral content statistics are shown in Table 6, with units of weight percentage (wt%).

[0074] Table 6. Statistical results of mineral content in discharged tailings (wt%)

[0075]

[0076] The results showed that the magnetite content in the sample was 0.30%; the main sulfur-bearing minerals were pyrite and pyrrhotite, with contents of 1.55% and 0.06%, respectively; the main copper-bearing mineral was chalcopyrite, with a relatively small content; the phosphorus-bearing mineral apatite content was 0.27%; the main non-metallic minerals were silicate minerals pyroxene and andradite, with contents of 52.06% and 23.58%, respectively, followed by carbonate mineral calcite with a content of 6.10%, and small amounts of silicate minerals such as albite, amphibole, mica, and serpentine; other minerals were present in small amounts.

[0077] This embodiment achieves efficient and synergistic recovery of iron and sulfur resources from copper tailings through a process of "magnetic roughing-magnetic cleaning-desulfurization flotation-tailings classification and recycling" and "separation flotation-re-magnetic separation-thickening underflow magnetic separation-disc magnetic separation" for tailings separation. The resulting qualified iron concentrate (63.54% iron, 1.76% sulfur) yielded 25.70%; high-sulfur iron concentrate (54.62% iron, 19.93% sulfur) yielded 9.54%; and the discharged tailings had an iron grade of 14.79%. The iron grade of the iron concentrate fully meets the quality standards for blast furnace iron concentrate in the steel industry, and the yield is as high as 25.70%. The high-sulfur iron concentrate also meets the market sales requirements for high-sulfur iron concentrate and can be directly used as a base material for deep processing of sulfur resources, realizing the resource utilization of sulfur. Meanwhile, the iron grade of the discharged tailings decreased to 14.79%, a reduction of 19.47% compared to the 34.26% iron grade of the raw tailings. This significantly improved the resource recovery rate, and the heavy metal content of the discharged tailings was greatly reduced, meeting environmental emission requirements. The tailings can be directly stored in tailings ponds or further used for filling mined-out areas, greatly reducing the land occupation and environmental risks associated with tailings storage.

[0078] In summary, this embodiment fully verifies the scientific validity and feasibility of the proposed process. It not only achieves the purification of high-value iron concentrate and the resource utilization of high-sulfur by-products in copper tailings, but also achieves the goals of tailings reduction and environmentally compliant emissions. It provides a replicable and scalable technical paradigm for the large-scale comprehensive utilization of similar copper tailings, and has significant resource, economic, and ecological benefits.

Claims

1. A method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings, wherein the copper tailings include copper beneficiation tailings generated from flotation and scavenging operations in a copper ore beneficiation plant and separation tailings generated from copper-sulfur separation flotation operations, characterized in that... The following steps are adopted: S1: Copper tailings processing: "Magnetic roughing-magnetic cleaning-desulfurization flotation, tailings classification-coarse sand magnetic separation and recycling" ① Magnetic roughing separation: Copper tailings with an iron grade of 30%~35% are subjected to magnetic roughing separation to obtain magnetic roughing concentrate with an iron grade of 55%~60% and magnetic roughing tailings with an iron grade of 12%~16%. ② Magnetic Concentration: Magnetic concentration is carried out on the magnetic roughing concentrate to obtain magnetic concentrate with an iron grade of 60%~65% and a sulfur grade of 5%~8% and magnetic tailings with an iron grade of 14%~18%. ③ Desulfurization flotation: The magnetically concentrated concentrate is fed into the iron desulfurization flotation operation to obtain desulfurized froth-high sulfur iron concentrate with an iron grade of 58%~62% and a sulfur grade of 18%~22%, as well as iron concentrate with an iron grade of 62%~66% and a sulfur grade of 1%~3%. ④ Tailings Classification - Coarse Sand Magnetic Separation and Recycling: The tailings from magnetic coarse separation and magnetic fine separation are mixed and fed into a hydrocyclone for classification, resulting in classified coarse sand with an iron content of 13%~18% and classified fine sand with an iron content of 14%~17%. The classified coarse sand is then subjected to coarse sand magnetic separation to obtain coarse sand magnetic concentrate with an iron content of 40%~45% and a sulfur content of 5%~10% and coarse sand magnetic tailings with an iron content of 12%~16% and a sulfur content of 0.2%~1%. The coarse sand magnetic concentrate is returned to the magnetic fine separation operation to achieve resource recycling. S2, Tailings separation via flotation followed by magnetic separation ① Separation and flotation: Separate flotation is carried out on the tailings with iron grade of 32%~36% and sulfur grade of 20%~25% to obtain copper concentrate 2 with copper grade of 4%~8% and re-selected copper tailings with iron grade of 0.2%~1% and sulfur grade of 22%~25%. ② Re-selection and magnetic separation: The copper tailings are subjected to re-selection and magnetic separation to obtain re-selection tailings magnetic concentrate with iron grade of 55-60% and sulfur grade of 16-20%, and re-selection tailings magnetic tailings with iron grade of 30-35% and sulfur grade of 22-26%. S3, Concentration - Fine Sand Magnetic Separation - Disc Magnetic Separation ① Concentration: The graded fine sand obtained in step S1 ④ and the re-selected tailings obtained in step S2 ② are fed into a thickener for concentration to obtain thickener underflow with an iron content of 15%~18%. ② Fine sand magnetic separation: Fine sand magnetic separation is performed on the underflow of the thickener to obtain fine sand magnetic concentrate with an iron content of 52%~56% and a sulfur content of 10%~12%, as well as fine sand magnetic tailings with an iron content of 13%~16%. ③ Disc magnetic separation: Fine sand tailings are subjected to disc magnetic separation to obtain disc magnetic concentrate with iron content of 27%~30% and sulfur content of 18%~21%, as well as tailings with iron content of 12%~16%. The fine sand magnetic concentrate obtained in step S3②, the disc magnetic concentrate obtained in step S3③, the desulfurization foam obtained in step S1③, and the re-selection tailings magnetic concentrate obtained in step S2② are combined and sold directly as high-sulfur iron concentrate.

2. A method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings as described in claim 1: In step S1, both magnetic roughing and magnetic cleaning are performed using a CTB type magnetic separator, wherein the magnetic roughing uses a CTB1021 type magnetic separator with a magnetic field strength of 2000-2500 Gs; and the magnetic cleaning uses a CTB1024 type magnetic separator with a magnetic field strength of 1500-2000 Gs.

3. A method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings as described in claim 1: In step S1 ③, the pulp concentration of the desulfurization flotation operation is 15% to 25%, butyl xanthate is used as the iron mineral collector, and No. 2 oil is used as the frother; wherein the dosage of butyl xanthate is 80 to 120 g / t, the dosage of No. 2 oil is 15 to 25 g / t, and the flotation time is 2 to 5 min.

4. A method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings as described in claim 1: In step ④ of S1, the hydrocyclone classification operation uses hydrocyclones with a specification of φ400~φ600mm and a classification pressure of 0.15~0.25MPa; the coarse sand magnetic separation uses a CTB1021 magnetic separator with a magnetic field strength of 800~1200Gs.

5. A method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings as described in claim 1: In step S2①, the separation flotation uses pentyl xanthate as the collector and No. 2 oil as the frother; wherein the amount of collector is 120-180 g / t, the amount of No. 2 oil is 25-35 g / t, and the flotation time is 3-6 min.

6. A method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings as described in claim 1: In step S2 ②, the magnetic separation is performed using a CTS1021 magnetic separator with a magnetic field strength of 2700-3200 Gs.

7. A method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings as described in claim 1: In step S3 ②, the fine sand magnetic separation adopts a CTB1021 type magnetic separator with a magnetic field strength of 2800~3200Gs.

8. A method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings as described in claim 1: In step S3 ③, the disc magnetic separation adopts a Φ1200mm disc magnetic separator with a magnetic field strength of 2800~3200 Gs.

9. A method for recovering iron concentrate and high-sulfur iron concentrate from copper tailings as described in claim 1: the process parameters of each step S1, S2 and S3 are adjusted in a coordinated manner so that the comprehensive iron grade of the product sold directly as high-sulfur iron concentrate is 50% to 60% and the comprehensive sulfur grade is 10% to 25%.

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